Earlier, the relatives linked arms and chanted "Malaysian government has cheated us" and "Malaysia, return our relatives" as they marched peacefully and held banners.

The relatives' grief and anger was unleashed last night, after Malaysian Prime Minister Najib Razak, announced that Malaysia Airlines Flight MH370, had crashed in the southern Indian Ocean killing all 239 people on board.

The aircraft vanished more than two weeks ago while flying to Beijing from Kuala Lumpur.

Bad weather hampers search efforts

Meanwhile, bad weather and rough seas have forced the suspension of the search for the missing plane.

Recovery of wreckage of the Boeing 777 could unlock clues about why the plane had diverted so far off course.

Theories range from a hijacking to sabotage or a possible suicide by one of the pilots, but investigators have not ruled out technical problems.

An international air and sea search in the area yesterday spotted several floating objects that might be parts of the plane and an Australian navy ship was close to finding possible debris, Australian Prime Minister Tony Abbott said.

However, the Australian Maritime Safety Authority said gale force winds, heavy rain and low cloud meant planes could not fly safely to the zone today, and waves of 6m or more forced the navy ship from the area.

"AMSA has consulted with the Bureau of Meteorology and weather conditions are expected to improve in the search area in the evening and over the next few days.

"Search operations are expected to resume tomorrow, if weather conditions permit," AMSA said in a statement.

Some relatives of those on board first received the news that the search for survivors was over in a Malaysia Airlines SMS message which said: "We have to assume beyond all reasonable doubt that MH370 has been lost and none of those on board survived."

There were hysterical scenes at the Beijing hotel where many of the relatives of those on board were staying. Most of the passengers on the flight were Chinese.

A group reportedly representing families issued a statement describing the Malaysian airline, government and military as “executioners" who constantly tried to delay and deceive them.

"We will take every possible means to pursue the unforgivable crimes and responsibility of all three," said the statement on the microblog of the Malaysia Airlines MH370 Family Committee.

Malaysia Airlines said in a statement that it would make arrangements to fly relatives to Australia once it had approval from the investigating authorities.

Mystery 'may never be solved'

Even if searchers are able to miraculously pluck Malaysia Airlines flight 370's "black box" from the depths of the vast Indian Ocean, experts say it may not solve one of aviation's greatest mysteries.

Planes, ships and state-of-the-art tracking equipment are hunting for any trace of the passenger jet, which Malaysia said crashed in the forbidding waters after veering far from its intended course.

They face a huge challenge locating the Boeing 777's "black box", which holds vital clues to determining what caused the plane to vanish on 8 March.

But experts believe the flight data recorder and cockpit voice recorder may not yield answers on the riddle of how and why the plane diverted an hour into the flight, and embarked on a baffling journey to the southern reaches of the Indian Ocean.

The data recorder details the aircraft's path and other mechanical information for the flight's duration, and "should provide a wealth of information", US-based aviation consultancy firm Leeham Co said in a commentary.

But the cockpit voice recorder, which could reveal what decisions were made by those at the helm and why, retains only the last two hours of conversations before the plane's demise.

That means potentially crucial exchanges surrounding the initial diversion, which took place halfway between Malaysia and Vietnam, will be lost.

"Clearly, it won't reveal anything that happened over the Gulf of Thailand – this will have been overwritten by the end of MH370," it said.

Leeham added that it also remains to be seen whether the cockpit recorder will contain anything pertinent about the plane's final two hours, when it is believed to have either ditched or run out of fuel.

Its exact location and the circumstances of its diversion remain a mystery. No distress signal was ever received.

Three scenarios have gained particular traction: hijacking, pilot sabotage, or a sudden mid-air crisis that incapacitated flight crew and left the plane to fly on auto-pilot for several hours until it ran out of fuel.

Malaysia has said it believes the plane was deliberately diverted by someone on board.

But with the travelling public and aviation industry hanging on every twist in the drama, no firm evidence has emerged from a Malaysian investigation to support any of the theories circulating.

British aviation expert Chris Yates said that even if the black boxes are found, "it seems unlikely that we will get that answer" of why the plane ended up thousands of kilometres off course.

"We still have no idea as to the mental state of the pilot and co-pilot, we have no idea if somebody managed to get into the cockpit to seize the aircraft, and we've certainly had no admissions of responsibility since this whole episode started," he told BBC television.